ISSN 10214437, Russian Journal of Plant Physiology, 2014, Vol. 61, No. 4, pp. 443–450. © Pleiades Publishing, Ltd., 2014.
RESEARCH PAPERS
The Physiological and Biochemical Responses to Freezing Stress of Olive Plants Treated with Salicylic Acid1 A. Hashempoura, M. Ghasemnezhada, R. Fotouhi Ghazvinia, and M. M. Sohanib a
Department of Horticultural Science, Faculty of Agriculture, University of Guilan, Rasht, Iran; fax: +981316690281; email:
[email protected] b Department of Biotechnology, Faculty of Agriculture, University of Guilan, Rasht, Iran Received May 21, 2013
Abstract—Oneyearold olive (Olea europaea L. cv. Zard) plants were treated with 0.5, 1, and 2 mM salicylic acid (SA) and then exposed to nonfreezing and freezing temperatures (–5, –10, and –20°C) for 10 h. Untreated plants served as a control. Exposure to freezing temperatures caused a considerable increase in ion leakage and lipid peroxidation in olive leaves. Treatment with suitable exogenous SA (1.0 mM) prevented the increase in the ion leakage and lipid peroxidation caused by freezing temperatures, especially at –5 and –10°C. SAinduced freezing tolerance was accompanied by increased activities of antioxidant enzymes, such as gua iacol peroxidase, catalase, ascorbate peroxidase, and polyphenol oxidase, as compared to control plants. Pro line, total phenolic content, and antioxidant capacity of olive leaves were declined significantly after exposure to freezing temperature, and their content decreased with lowering of freezing temperatures, while treatment with 1 mM SA induced a significant increase in their content. As a summary of these results, suitable concen tration of SA (1 mM) could enhance freezing tolerance of olive plant by increasing antioxidant enzyme activ ities and decreasing MDA content through cell membrane integrity maintenance. Keywords: Olea europaea, freezing stress, salicylic acid, antioxidant enzymes, ion leakage, lipid peroxidation DOI: 10.1134/S1021443714040098 1
INTRODUCTION
Freezing stress (
